Technology is altering consumers' relationship with cars. Do you purchase, lease, or even go without owning a vehicle? Here are key trends to track.

Cars last longer. A record high 271 million automobiles are registered in the United States, but they aren't all shiny and new. The average vehicle is now a whopping 11.7 years old, and you can credit tech in part for that longevity, says IHS Markit auto analyst Mark Seng. In addition to improved overall quality and better resistance to rust, he says, the "increasing use of electronics and sensors instead of mechanical parts" helps keep cars running longer.

Online tools simplify buying. Services such as Autotrader, Shift, and Peddle (and, of course, the AAA Auto Buying Program) make it easy to price, buy, and sell vehicles. These platforms are also getting surprisingly sophisticated: AutoTempest scours and compares multiple sites, including Craigslist, to find the ride you want from a nearby seller.

Cars are becoming like smartphones. A growing subset of drivers has become so enamored with "it" cars—such as the Tesla Model 3 and the Chevy Bolt—that they'll happily put down deposits before a single vehicle has rolled off the assembly line. At presstime, the waiting list for Tesla's Model 3 had 455,000 names on it and was growing at a rate of 1,800 new reservations per day.

Buyers are willing to go without. All-electric vehicles and other new technologies such as hydrogen cells are still taking baby steps. Some buyers are willing to delay their purchases until dramatic innovations materialize. In some cases, they're forgoing a car altogether in the meantime: "My Ford Focus Electric lease ends in four days," says Ken Roach, a Seattle engineer, "so I'm going to be taking the train, riding the bus, or riding my bike until the model I want becomes available."

Sharing is replacing ownership. Why buy a car at all? That's the question a lot of people—particularly urban millennials—are asking these days. It's often easier for city dwellers to request an Uber or a Lyft. For longer trips, you can hop in a short-term rental such as a Zipcar or, in Oakland and Berkeley, Calif., a GIG Car Share, powered by AAA. Car sharing is on track to become a monstrous $16.5 billion market by 2024.